SPF stands for “Sender Policy Framework.” It is an email authentication method used to verify the legitimacy of an email sender’s identity. SPF helps prevent email forgery by allowing the receiving mail server to check whether the incoming email originated from an authorized server.
When an email is sent, the receiving mail server can perform an SPF check by querying the DNS (Domain Name System) records of the sender’s domain. The SPF record is a specific type of DNS record that lists the authorized email servers allowed to send email on behalf of that domain. The SPF record contains a list of IP addresses or domain names that are considered legitimate senders for that domain.
During the SPF check, the receiving mail server compares the source IP address of the incoming email with the authorized IP addresses or domains listed in the SPF record. If the source IP address matches one of the authorized entries, the email passes the SPF check. Otherwise, it may be flagged as potentially forged or spam.
SPF helps combat email spoofing, where attackers try to send emails that appear to come from a legitimate domain but are actually sent from unauthorized servers. By implementing SPF, domain owners can specify which servers are authorized to send email on their behalf, increasing email security and reducing the likelihood of email fraud and spam.
It’s worth noting that SPF is just one of several email authentication methods, including DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting, and Conformance). These methods work together to provide a more robust email authentication framework, helping to improve email deliverability and protect against malicious activities.